Raspberry Pi 樹莓派編譯新核心

前陣子在家門口踢到一個…

Raspberry Pi 二代目 Model B,然後就 過著開開心心的生活 開始想把一堆東西裝上去然後不知道要幹嘛!?書房的 Hub 滿了,所以我就要拿出之前買的 小米隨身WiFi 拿出來插上…

就會發現,什麼事都沒有發生。因為…Driver 沒有進 Kernel 根據非官方 Github 上的 Repo 顯示:

This repository is based on the original driver released by MediaTek which was rejected from Linux kernel because of the poor code quality.

嗯!所以展開自編之路…

故事一波三折,曲折離奇…先進入正題

準備環境

我的環境是 Ubuntu 64bit

λ ~/uname -a
Linux ubuntu 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15 01:58:42 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

創一個資料夾來放等等要下載的東西

λ ~/mkdir ~/rasp

注意 以下的 git clone 會帶 --depth 1 表示我們只抓預設 branch 的最後一個 commit 這是為了加快下載速度以及節省空間

Raspberry Pi Toolchain (download)

λ ~/rasp/ git clone https://github.com/raspberrypi/tools --depth 1

toolchain 位於下面位置

λ ~/rasp/ ls tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-*
tools/../../bin/arm-linux-gnueabihf-addr2line
tools/../../bin/arm-linux-gnueabihf-ar
tools/../../bin/arm-linux-gnueabihf-as
tools/../../bin/arm-linux-gnueabihf-c++
tools/../../bin/arm-linux-gnueabihf-c++filt
tools/../../bin/arm-linux-gnueabihf-cpp
tools/../../bin/arm-linux-gnueabihf-ct-ng.config
tools/../../bin/arm-linux-gnueabihf-dwp
tools/../../bin/arm-linux-gnueabihf-elfedit
tools/../../bin/arm-linux-gnueabihf-g++
tools/../../bin/arm-linux-gnueabihf-gcc
tools/../../bin/arm-linux-gnueabihf-gcc-4.8.3
tools/../../bin/arm-linux-gnueabihf-gcc-ar
tools/../../bin/arm-linux-gnueabihf-gcc-nm
tools/../../bin/arm-linux-gnueabihf-gcc-ranlib
tools/../../bin/arm-linux-gnueabihf-gcov
tools/../../bin/arm-linux-gnueabihf-gdb
tools/../../bin/arm-linux-gnueabihf-gfortran
tools/../../bin/arm-linux-gnueabihf-gprof
tools/../../bin/arm-linux-gnueabihf-ld
tools/../../bin/arm-linux-gnueabihf-ld.bfd
tools/../../bin/arm-linux-gnueabihf-ldd
tools/../../bin/arm-linux-gnueabihf-ld.gold
tools/../../bin/arm-linux-gnueabihf-nm
tools/../../bin/arm-linux-gnueabihf-objcopy
tools/../../bin/arm-linux-gnueabihf-objdump
tools/../../bin/arm-linux-gnueabihf-pkg-config
tools/../../bin/arm-linux-gnueabihf-pkg-config-real
tools/../../bin/arm-linux-gnueabihf-ranlib
tools/../../bin/arm-linux-gnueabihf-readelf
tools/../../bin/arm-linux-gnueabihf-size
tools/../../bin/arm-linux-gnueabihf-strings
tools/../../bin/arm-linux-gnueabihf-strip

這邊我選用 gcc-linaro-arm-linux-gnueabihf-raspbian-x64 作為我待會要 cross compile 的 toolchain

Raspberry Pi Kernel (cross-compile + update)

λ ~/rasp/ git clone https://github.com/raspberrypi/linux --depth 1

進入資料夾後依序執行

1.先把建置環境清乾淨

λ ~/rasp/linux/ make mrproper

2.把機器上現有的 Kernel Config 倒出來 (在板子上執行)

# zcat /proc/config.gz > .config

然後再把這個 .config 檔案傳回 linux 資料夾底下

3.再來先設定好 CROSS_COMPILE 環境變數後,執行 make oldconfig

λ ~/rasp/linux/ export CROSS_COMPILE=~/rasp/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-
λ ~/rasp/linux/ ARCH=arm make oldconfig

PS1. 這邊 ARCH 記得要指定為 arm 不然會跑到你本機的架構 (ex: x86)
PS2. 執行 oldconfig 有可能會跳出一些選項要你選擇,是因為先前的 Kernel 沒有這些 options 新版本可能會有差異

4.最後執行 make

λ ~/rasp/linux/ ARCH=arm make

TicToc~TicToc 跑完後你就有全新的 Kernel 啦!

產出的檔案在 arch/arm/boot/Image

λ ~/rasp/linux/ ls arch/arm/boot/Image -alh
-rwxrwxr-x 1 zack zack 8.1M Apr 27 21:03 arch/arm/boot/Image

複製到機器上,/boot/kernel_new.img 然後修改 /boot/config.txt (怎麼會用附檔名 txt 呀好詭異 XDDD),加入一行 kernel=kernel_new.img ,原本的 kernel 先改個名子放旁邊。

[email protected]:/boot# cat config.txt
kernel=kernel_new.img

再來回到桌機這邊準備一下新的 Kernel modules

λ ~/rasp/ mkdir modules
λ ~/rasp/linux/ ARCH=arm INSTALL_MOD_PATH=~/rasp/modules make modules_install

新版本的 modules 就會跑到 ~/rasp/modules 囉,把它們全部 SCP 到板子上的 /lib 取代
(如果擔心玩壞可以先備份)

萬事搞定,直接下 Reboot 就可以看到裝著新的 Kernel 的 Raspberry Pi 啦~

[email protected]rypi:/boot# dmesg
[ 0.000000] Booting Linux on physical CPU 0xf00
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
[ 0.000000] Linux version 3.18.11-v7+ ([email protected]) (gcc version 4.8.3 20140303 (prerelease) (crosstool-NG linaro-1.13.1+bzr2650 - Linaro GCC 2014.0
3) ) #1 SMP PREEMPT Mon Apr 27 21:03:05 CST 2015
[ 0.000000] CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] Machine: BCM2709
[ 0.000000] cma: Reserved 8 MiB at 0x3d800000
[ 0.000000] Memory policy: Data cache writealloc
[ 0.000000] On node 0 totalpages: 253952
[ 0.000000] free_area_init_node: node 0, pgdat 8080f480, node_mem_map bd033000
[ 0.000000] Normal zone: 1984 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 253952 pages, LIFO batch:31
[ 0.000000] [bcm2709_smp_init_cpus] enter (8620->f3003010)
[ 0.000000] [bcm2709_smp_init_cpus] ncores=4
[ 0.000000] PERCPU: Embedded 10 pages/cpu @bd006000 s11456 r8192 d21312 u40960

參考資料